Area Calculator

Calculate the area and perimeter of rectangles, squares, circles, triangles, trapezoids, ellipses and sectors.

How do I calculate the area of a shape?

Pick the shape and enter its measurements: a rectangle’s area is length × width, a circle’s is π × radius², a triangle’s is ½ × base × height and a trapezoid’s is (a + b) ÷ 2 × height. The calculator shows the area, the perimeter where defined and the formula used.

Examples

Rectangle 5 × 3 m → 15 m², perimeter 16 m.
Circle with radius 5 m → 78.54 m².
Triangle with base 5 and height 3 → 7.5.

To convert between units (m², ft², acres), use the Area Converter.

Frequently asked questions

How is the ellipse perimeter calculated?

With Ramanujan’s approximation, accurate to a fraction of a percent.

Can I use any unit?

Yes, results are in the unit you type, squared.

Is it free?

Yes.